NumCosmoGalaxyShapeFactorupdate_data_at_nodes_sigma

Refreshes data‘s cached surface mass density Sigma(R) used by the fixed-nodes path, using data‘s own cached projected radius as an input. Unconditional: call only when nc_galaxy_shape_factor_get_radius_hash() or nc_galaxy_shape_factor_get_optzs_hash() changed, and only after nc_galaxy_shape_factor_update_data_radius() in the same cycle if that one also needs to run — this assumes data‘s cached projected radius is already current (same ordering contract as update_data_optzs()).